Process of tanning hides.



,UNITED fsrATns PATENT OFFICE.

WILLIAM cfRoAcH, OF CINCINNATI, OHIO, AND ALBERT c. ROACH, OF NEWPORT, KENTUCKY, ASSIGNORS TO THE ciNciNNAri CHROME. LEATHER COMPANY, OF. CINCINNATI, OHIO, A CORPORATION OF OHIO.

Specification of Letters Patent.

PROCESS OF' TANNING HIDES".

Patented Dec. 25,1906.

Ap li ati fil d June 15,1904. Serial No. 212,698. Y

To all whof m it may concern: Be it known that W6,WILLIAM. G. RoAcH,

' residing at Cincinnati, in the county of Hamilton and State of Ohio, and ALBERT O. RoAoH, residing at Newport, in the county of Campbell and State of Kentucky, citizens of the UnitedStates, have invented certain new and useful Improvements in Processes of Tanning Hides, ofwhichthe following is a specification. I

The object of our invention is to provide an improved process for the metallic tanning of hides; and our invention consists in the process hereinafter described and claimed.

' The hides are prepared for tanning in the usual way and then placed in a'chromic-acid bath until thoroughly permeated by the chromic acid. This bath may consist of four pounds of bichromate of potash, four pounds of hydrochloric acid, and from four to six hundred pounds of water, which will form a 'chromic-acidbath, as will be readily understood by those skilled in the art.

substance.

After the hide has-been thoroughly permeated with chromic acid We subject it to a bath of an organic reducing agent, such as glycerin, or glucose, or some other saccharine The proportions of this bath I may be five poundsof glucose or other reduci on the fibers of the hide.

ing agent to five pounds of water. We allow the hide to become thoroughly saturated with this solution, which will take about thirty minutes;

Under the conditions of application there will be no substantial reducing action between the chromic acidand. glucose for a con- "siderable length of time, so that the glucose willuniformly penetrate the hide before any substantialreduction takes place. This permits intimate and uniform association betweenthe chromic acid and glucose before reduction, so that when reduction does take .place the chrome-oxid is uniformly deposited Thus it will be seenthat the two substances, glucose and chromic acid, are introduced into the fiber of the hide in a substantially inactive chemical state and become intimatelyand uniformly associated together and with the fiber of the hidebefore reduction takes place.

. The next step in our process is to remove the hide from the glucose solution and subject it to a bath of hot vapors, such as steam leather.

' i not under pressure. This may be done by hangingthe hides in a room containing steam. A convenient method for introducing the steam to the chamber is by means of steam-supply pipes arranged in any convenient manner in the chamber and provided with holes in their walls adapted to permit escape of the steam into the chamber. The hides are left hanging in the steam-chamber until the chromic acid has been thoroughly reduced. With thin hides this would take about one-half hour and with thicker hides a proportionately longer time.- The effect is to cause the chromic acid to be reduced to chrome-oxid, and the conditions are most favorable for causing that oxid to combine thoroughly with the gelatinous substances of the hide. The water-vapors present serve to maintain the softness of the hides during reduction. The reduction taking place uniformly throughout the hides Will 08.1186 a uniform deposit of chrome-oxid on the fibers, and consequently a uniformly tanned We are not prepared to state the exact chemical reaction which'takes place in the hide; but we have found that the chromic acid is thoroughly reduced and that the chromic oxid combines fully with the gelatinous substances of the hide.

After the'hide has undergone this aforesaid step it is a marketable leather which does not need any further stuffing to make it retain its plumbness. This leather is suitable for such purposes as belting, upholstering, and enameled leather.

In cases where it is desired to have a greased leather it may be stuffed in the ordinary manner.

We claim as our,invention 1 .1. The process of tanning hides which con-' sists in introducing into the fibers of the hide, in a substantially inactive chemicalv state, substances containing the elements of a tanning matter adapted to be released by reaction between said substances, and then subj ecting the hidesto the action of steam until the reaction 'takes place, substantially as specified.

2. The process of tanning hides which consists in introducing into the fibers of the hide, in a substantially inactive chemical state, a reducible metallic compound and a reducing agent; and subjecting the hides to the action of steam until reduction takes place, substantially as specified.

3. The process of tanning hides which consists in introducing into the fibers of the hide, in a substantially inactive chemical state, a

reducible metallic compound and an organic tion of steam, substantially as specified.

5. The process of tanning hides which consists in subjecting them to the action of chromic acid, then of a saccharine solution and then subjecting them to the action of heat in the presence of vapors to promote the reduction of the chromic acid.

6. The process of tanning hides which consists in subjecting them to the action of chromic acid, then to that of a reducing agent and then to the action of steam substantially as described.

WILLIAM G. ROACH. ALBERT C. ROAOH.

Witnesses W. F. MURRAY, A. MoCoRMAoK. 

